1. 1 Overview of the Tactical Turbulence Project John K. Williams Contributors include Bob Barron, Gary Blackburn, Jason Craig, Cathy Kessinger, Greg Meymaris, Julia Pearson, Bob Sharman, Tenny Lindholm and Gerry Wiener WTIC Tactical Turbulence Kickoff Meeting William J. Hughes Technical Center Atlantic City, NJ June 19, 2014

2. 2 Tactical turbulence project objective Overall research project goals –Identify a recommended method for presenting tactical turbulence alert –Demonstrate the feasibility of implementing the tactical turbulence alert with the necessary latency via an Aircraft Access to SWIM (AAtS) connection –Include tactical turbulence alerting function in the Minimum Weather Service recommendations Planning project goals –Plan service analyses to assess feasibility –Identify preliminary high level capabilities and implementations for tactical turbulence alerting in the cockpit –Identify associated concepts of use –Anticipated outcome: FAA approved Project Plan for an NIEC simulator evaluation

3. 3 What do we mean by “tactical turbulence”?

4. 4 NOT turbulence forecasts Graphical Turbulence Guidance (GTG), available on Operational ADDS (http://aviationweather.gov/adds) 13 km horizontal resolution, 1000 ft vertical resolution, 0-12 hour forecasts of turbulence for FL100- 450 based on WRF RAP NWP model Forecast quantity is EDR (= ε 1/3, m 2/3 s -1 ) ICAO standard Scale of about 0-1 Currently, GTG Is mainly for Clear Air Turbulence (CAT) and does not specifically include turbulence due to storms or mountain waves

5. 5 NOT radar reflectivity Reflectivity is related to the radar returned power, which depends on the phase, number and size distribution of atmospheric hydrometeors Often related to storm intensity, but not necessarily turbulence 1:45 UTC May 26, 2011 Composite reflectivity and SIGMETs Echo tops and ASDI

6. 6 “Tactical turbulence” IS A rapidly updated, high-resolution view of the current turbulence state of the atmosphere Components –Aircraft measurements of turbulence Pilot reports (PIREPs) In situ EDR reports –Doppler radar measurements of turbulence –Turbulence inferences Fusion of data from radar, satellites, lightning detection networks, NWP models, etc. Combination of all of these: –Graphical Turbulence Guidance Nowcast (GTG-N)

7. 7 Why is tactical turbulence important?

8. 8 Motivation for tactical turbulence Current information available to pilots and dispatchers is not adequate for accurately identifying tactical turbulence hazards and can be misleading. –PIREPs and in situ EDR reports identify turbulence only where other aircraft have encountered it –GTG forecasts do not adequately identify small-scale, rapidly- evolving turbulence, e.g., convective turbulence from thunderstorms –Radar reflectivity is related to hydrometeors size and density, not turbulence intensity –Convective SIGMETs are large, long-lived, and non-specific –Turbulence SIGMETs don’t include convective turbulence, and are generally issued only after a severe PIREP is recorded –Airborne Doppler radar turbulence detection covers a limited region and is primarily for pilot use, not shared situational awareness Given the potentially rapid evolution of turbulence, latency of cockpit alerts must be minimized.

9. 9 Motivation for GTG-N Doppler radar can measure only in-cloud turbulence in regions with radar coverage –Providing alerts based only on Doppler radar measurements could miss some locations and significant sources of turbulence: out-of-cloud convectively-induced turbulence (CIT), clear-air or mountain wave turbulence –Graphical display of only Doppler radar turbulence could be misleading due to incomplete coverage GTG-N combines turbulence observations, measurements, inferences and forecasts to provide a rapidly-updated, real- time, high-resolution, comprehensive view of current turbulence conditions –Thus, GTG-N is the ideal product for providing tactical turbulence information

10. 10 COMPONENT OF GTG-N: Doppler Radar Turbulence Measurement: NEXRAD Turbulence Detection Algorithm (NTDA)

11. 11 Based on Doppler NEXRAD data –Uses Doppler Spectrum Width (SW), quality controlled, scaled and averaged to produce EDR measurements on each radar polar grid Polar grids are combined into a CONUS 3-D mosaic –2 km horizontal, 3,000 ft vertical, 5 minute time resolution currently –Uses data from 142 NEXRADs –Real-time at NCAR since 2008 Provides in-cloud turbulence detection in radar-covered regions devoid of signal contamination NEXRAD Turbulence Detection Algorithm (NTDA) NTDA (Radar by Radar) NTDA (Radar by Radar) NTDA (Radar by Radar) Level 2 NEXRAD data NTDA (Radar by Radar) NTDA Mosaic

12. 12 Sample NTDA mosaic animation CIDD research display: NTDA mosaic 6-hr loop on 11 August 2008, 36,000 ft overlaid are in situ EDR measurements from United Airlines B-757s

13. 13 NTDA EDR DBZ NTDA EDR DBZ NTDA EDR vs. reflectivity mosaics 28 September 2007 (2 km horizontal resolution) Colorado Kansas Colorado Kansas

14. 14 NTDA EDR vs. reflectivity mosaics 28 September 2007 (2 km horizontal, 3000 ft vertical resolution) NTDA EDR DBZ 14 km52 km 8 km

15. 15 Case 1: United Flight 1727 severe turbulence encounter over N. Gulf of Mexico, 4 April 2012 A Boeing 737, UA Flight 1727 from Tampa to Houston ASDI data: altitude declined from FL 380 to FL 321 in one minute near 11:57 UTC Five passengers and two flight attendants were injured, according to United Airlines At least three people were transported to a hospital The pilots declared an emergency, and emergency personnel met the aircraft after landing The flight left Tampa International Airport at 6:30 a.m. EDT and arrived in Houston at 7:47 a.m. CDT. 15

16. 16 Case 1: United Flight 1727 severe turbulence encounter over N. Gulf of Mexico, 4 April 2012 16 FL 360 Reflectivity, 11:50 UTC FL 360 NTDA EDR, 11:50 UTC Reflectivity cross-section, 11:50 UTC NTDA EDR cross-section, 11:50 UTC

17. 17 Case 1: United Flight 1727, cont. UCAR Confidential and Proprietary. © 2012, University Corporation for Atmospheric Research. All rights reserved. 17 FL 360 Reflectivity, 12:05 UTC FL 360 NTDA EDR, 12:05 UTC Reflectivity cross-section, 12:05 UTC NTDA EDR cross-section, 12:05 UTC

18. 18 Case 2: UA 1632 severe turbulence encounter over Eastern Texas, 13 June 2012 01:17 UTC, FL225 NSSL Composite Reflectivity, 1:20 UTC NTDA EDR at FL270, 1:20 UTC PIREP: UUA /OV DAS180025/TM 0117/FL225/TP B737/TB SEV/RM NO DMG OR INJ AWC-WEB:KZHU 18

19. 19 Case 2: UA 1632, cont. Reflectivity cross-section 1:20 UTC NTDA EDR cross-section 1:20 UTC 19

20. 20 Case 2: UA 1632, cont. Encounter location (~10 km radius disc) NTDA EDR from the 5.0° sweep from KHGX (Houston NEXRAD) at 1:18 UTC 13 June 2012. 20

21. 21 NTDA United Airlines cockpit uplink demonstration (2005-2007 )

22. 22 A real-time NTDA cockpit uplink demonstration with United Airlines was performed in 2005-2007.

23. 23 NTDA demo: Java web-accessible display NTDA turbulence, 0040 UTC on 27 July 2005 Moderate turbulence Severe turbulence In situ turbulence reports Vertical cross-sections of turb. and refl. 23

24. 24 Used ASDI track and position data ASDI = Aircraft Situation Display to Industry ASDI data include flight plans (waypoint sequence) and real-time aircraft positions (1-min updates) NCAR processed ASDI route and position data for all United Aircraft and created aircraft-centric horizontal and vertical maps of turbulence 0-100 nmi ahead every 5 minutes in real-time United Airlines line check airmen who registered their flights in a web form received uplinks of the maps via ACARS text messages when the extent, proximity, or severity of turbulence exceeded specified thresholds Post-flight, pilots and dispatchers could review the text maps and provide feedback on their accuracy and usefulness

25. 25 NTDA uplink /EXPERIMENTAL TURBULENCE FI UAL███/AN N███UA UPLINK -- 05 Sep 2006 21:38:13Z FL 300 orient. 83 deg '+'=waypoint, '*'=route, 'X'=aircraft at 38.3N, 80.6W ' '=no_data, 'o'=smooth, 'l'=light, 'M'=mod, 'S'=severe -----------------------(52 to IAD)------------------------ | * MM | * MM | l lll M * MMM | lollo * lMl | oolo * l | oo * | * |080 * M |llllllll ll * MM |lllllllllllllll l * lll |lllllllllollllllll * MMl l |MMllllllllooollllll * MMl l |MMMl lllllllllollll * MM l |MMMM llll llol ll * MM | MMMM ll * MMS | MMM * MSS | MM * MSS +PUTTZ + MSS | * SSSSSS MSS M | l S*SSSSSSSSS MSS M | lllS*SSSMSSSSS MSS l | lSMS*SMMMMSSSS MSS l | SSMM*MMMMMMMM MSS M | MM*SMMMMMMMMlllll MSS M | M*SSMMMMMMMMllllll MMM M | *MMMMMMMMMMMMMllll MMM | * MMlllMMMlMllllllM lll |040 * lllllllllllllllllMMl lll | * llllllllllllll llS | * llllllllll MMS | * lllllll SSS | * lllll SSS | * lll MMS | * l ll MM | * MM M | MM*MM o MSS | SM*MM MMM | MM *MM l MM | MMMSS S * l l lM | MMMSSM * lllllll o l |l MMMM * lllllo | MMMMM * llllll | M * lllll | SSS * llll ll | SSS M l * l lll | SSS Mlllll * llM | MM lMlllll * l -------|---------valid-|--------X--------|---------------- -90 +90|Left 40 2135Z (18 from 3819N/8058W) Right 40 Flight information Legend Route Severe turbulence Aircraft position Waypoint Vertical cross-section Moderate turbulence NTDA product uplinked into registered United Airlines flights within the CONUS 3 summer demonstrations in 2005- 7 over increasing domains –Boeing 737, Boeing 757, Boeing 777 Pilot feedback collected via web forms post-flight Statistical performance analysis showed drop-off after ~8 minutes 25

26. 26 NTDA uplink message at 2208 UTC /EXPERIMENTAL TURBULENCE FI UAL███/AN N███UA UPLINK -- 01 Jul 2006 22:08:10Z FL 360 orient. 88 deg '+'=waypoint, '*'=route, 'X'=aircraft at 43.2N, 86.3W ' '=no_data, 'o'=smooth, 'l'=light, 'M'=mod, 'S'=severe ---------------------------(25 to EJOYS)------------------ ll | * lll | * lll | lllll* lll l | ollll* lll M | oolll*l lll | llll * lll +MONEE llllllll + lll l | ll llllll * lll l | llll lllllll*ll lll l | oll lllllllll*ll lll l | ool lllllllll * lll | lllllll * lll | llllll * lll l | llllllll * lll l | olllllllll * lll l | ooo lllllll * Mll | o lllllll * lll | lllll * lll | lloo * lol | * llo | * lll | * lll l | ll * lll l | lll * lll l +GRUBB lll + lll |040 ll * ll | * | * -------|---------valid----------X------------------------- -90 +90|Left 40 2205Z (86 from BAE) Right 40 View toward left at about 2215 UTC Radar at ~2215 UTC (deviation began at 2213) NTDA turbulence display at 2210 UTC Ex: Unnecessary deviation 26

27. 27 COMPONENT OF GTG-N: Convectively-induced turbulence inference: Diagnosis of Convectively-Induced Turbulence (DCIT)

28. 28 DCIT Diagnoses CIT both in and above / around clouds –Outputs EDR and turbulence probabilities Operational data sources include –near-storm environment fields and turbulence diagnostics derived from NWP models (e.g., WRF-RAP) –lightning and satellite-derived features and turbulence signatures (e.g., overshooting tops) –3-D radar reflectivity and derived features –NTDA A data fusion technique is used to combine these data sources and infer likely regions of turbulence –automated in situ EDR reports used as “truth”

29. 29 DCIT Case Study May 26, 2011 01:45 UTC Composite reflectivity and SIGMETs Echo tops and ASDI DCIT probability, FL330DCIT probability, FL390 Note: DCIT estimates that there is more turbulence at FL390 than FL330, particularly near Chicago.

30. 30 Comprehensive tactical turbulence: GTG-Nowcast

31. 31 GTG Nowcast (GTG-N) GTG-N is a rapidly updated nowcast system driven by the most recent available turbulence information –Observations: In situ EDR, PIREPs, NTDA, DCIT, satellite data, … –Merged with GTG short term forecast –Currently updated every 15 min Output is gridded EDR GTG-N is part of GTG-3 (scheduled operational 2015) Developed to provide tactical turbulence information GTG-N GTG

32. 32 GTG-N example FL380, 21:00 UTC August 13, 2010 GTG 1hr Forecast GTG-N & next 15min verifying in situ EDRIn situ, PIREPs & NTDA GTG & DCIT 32

33. 33 SUMMARY

34. 34 Summary Current information available to pilots and dispatchers (e.g., turbulence forecasts, PIREPs, reflectivity, SIGMETs) is not adequate for accurately identifying tactical turbulence hazards and promoting common situational awareness, and can be misleading. GTG-N was designed to provide accurate, up-to-date tactical turbulence information –Combines NTDA, DCIT (CIT inference), GTG and recent turbulence observations to provide a comprehensive “nowcast” of current turbulence conditions Given the small scales and potentially rapid evolution of turbulence, dissemination and alerting methods must be high-resolution and low-latency.

35. 35 Questions?

36. 36 Extra Slides

37. 37 NCAR Research Applications Laboratory “Our mission is to conduct directed research that contributes to the depth of fundamental scientific understanding, to foster the transfer of knowledge and technology for the betterment of life on earth, and to support technology transfer that expands the reach of atmospheric science.” http://ral.ucar.edu/

38. 38 NCAR/RAL Aviation Applications Program Funding from FAA Aviation Weather Research Program, NASA, NOAA, private companies (no NSF base funds) AAP research areas include: –Radar remote sensing –Satellite applications –Numerical modeling –In–Flight Icing –Turbulence –Ceiling and Visibility –Consolidated Storm Prediction for Aviation (CoSPA) –Oceanic/Remote Weather –Terrain–Induced Wind Shear and Turbulence –FAA Sensor Network Assessment –Forecaster–Over–the–Loop Studies –Dissemination (e.g., Aviation Digital Data Service) –Weather Integration Into Decision Making –International Aviation Weather Systems http://ral.ucar.edu/aap/

39. 39 Sources of turbulence Source: P. Lester, “Turbulence – A new perspective for pilots,” Jeppesen, 1994 Clear-air Turbulence (CAT) Mountain wave Turbulence (MWT) Low level Terrain-induced Turbulence (LLT) Convective boundary Layer turbulence In-cloud turbulence Cloud-induced or Convectively- induced Turbulence (CIT) 39

40. 40 Numerical simulation: Convectively Induced Turbulence (CIT) 2-D simulation showing cloud, gravity waves, and turbulence (courtesy of Todd Lane) 26000 ft 33000 ft 39000 ft 46000 ft 52000 ft

41. 41 NTDA EDR at FL 120 at 22:05 UTC NTDA dBZ at FL 120 at 22:05 UTC Vertical x-section NTDA EDRVertical x-section NTDA dBZ Flight track of FFT283 Case 3: Frontier 283, 12 August 2013 ~22:06 UTC, FL130, moderate turbulence, 4 injuries

42. 42 Case 3: Frontier 283, cont NTDA EDR at FL 150 at 22:05 UTC

43. 43 Case 4: Airbus A340 severe turbulence encounter on 6 August 2003 Encounter at FL 310 over NE Arkansas, 20:57 UTC Vertical acc. from -0.9 to +2.3 in about 3 seconds 43 minor injuries, two serious From the NTSB Factual Report: …the flight crew noticed “a change in density, but did not get any radar echoes.” A few seconds later, the flight encountered severe turbulence. …seven FA’s hit the cabin ceiling and then the floor, one FA hit the ceiling then an armrest, and two FA’s were tossed through a galley. The trolleys…were lifted from the floor. Numerous food service items were tossed and broken throughout the cabin. The FAA inspectors…found damage to cabin interior, ceiling, seats, and galley. Ceiling panels were loose, hanging down, or pushed upward...aircraft structure and cables were exposed. KPAH 2.4° sweep NTDA EDR (  , 0 to 0.7 m 2/3 s -1 ) Encounter location light moderate severe smooth 43

44. 44 KPAH reflectivity 8 minutes prior: 15-30 dBZ Encounter location showing low values of radar reflectivity X NTDA EDR: 0.55-0.65 m 2/3 s -1 (severe) X NTDA indicates severe turbulence Case 4: Airbus A340, cont. 25 km

45. 45 NTDA limitations NTDA works best when turbulence is isotropic (the same in all directions) –Radars measure mostly horizontal wind fluctuations, but vertical can be most hazardous NTDA can only provide information at times, locations and resolution determined by the radar –E.g., at 60 miles range, 1° ≈ 1 mile, and there are large gaps between sweeps at high angles NTDA may not always filter out all non-atmospheric and measurement noise (e.g., lightning) Turbulence is fundamentally a statistical quantity, so there will always be differences between remote detection and aircraft measurements (and between different aircraft) 45

46. 46 NTDA limitations (cont.) Coverage near the ground is limited by radar geometry and ground clutter NTDA does not adjust for hydrometeor inertial effects –May not be accurate in heavy rain, hail NTDA works best when turbulence is well-developed and consistent with theoretical models –May not be true for new updrafts, thin shear layers NTDA is a measurement (backwards-looking), not a prediction NTDA 0015 UTC, FL 330 NTDA 0030 UTC, FL 330 United 967 turb. encounter, 21 July 2010 00:14 UTC 46

47. 47 Current FAA thunderstorm avoidance guidelines Don’t attempt to fly under a thunderstorm even if you can see through to the other side. Turbulence and wind shear under the storm could be disastrous. Do avoid by at least 20 miles any thunderstorm identified as severe or giving an intense radar echo. This is especially true under the anvil of a large cumulonimbus. Do clear the top of a known or suspected severe thunderstorm by at least 1,000 feet altitude for each 10 knots of wind speed at the cloud top. Do circumnavigate the entire area if the area has 6/10 thunderstorm coverage. Do regard as extremely hazardous any thunderstorm with tops 35,000 feet or higher whether the top is visually sighted or determined by radar.

48. 48 NTDA RT Demo System

49. 49 GTGN data sources Turbulence Nowcast 3D grid (GTGN) Airborne Observations In-situ reports PIREPs DCIT Algorithm Satellite Features Ground-based Radar Observations NTDA mosaic Turbulence Inferences Real-time Turbulence Observations Numerical Weather Prediction Model ASDI deviations ADS-B deviations Turbulence EDR Forecast Model (GTG)

50. 50 GTGN incorporation of NTDA Verification via in situ EDR reports shows that adding NTDA considerably improves GTGN skill Prediction of Moderate or Greater Turbulence